Estimating the concordance probability in a survival analysis with a discrete number of risk groups

A clinical risk classification system is an important component of a treatment decision algorithm. A measure used to assess the strength of a risk classification system is discrimination, and when the outcome is survival time, the most commonly applied global measure of discrimination is the concordance probability. The concordance probability represents the pairwise probability of lower patient risk given longer survival time. The c-index and the concordance probability estimate have been used to estimate the concordance probability when patient-specific risk scores are continuous. In the current paper, the concordance probability estimate and an inverse probability censoring weighted c-index are modified to account for discrete risk scores. Simulations are generated to assess the finite sample properties of the concordance probability estimate and the weighted c-index. An application of these measures of discriminatory power to a metastatic prostate cancer risk classification system is examined.     

Epidemiologic network inference

Statistics and Computing - In many epidemiologic models, a disease is assumed to spread along a contact network. We aim to infer this network, in addition to the epidemiologic model parameters,...     

Modeling Phytosanitary Risk of Unintended Commodity Use: The Example of U.S. Potato Exports to Mexico

Diversion of commodities from their intended use to an unintended use, e.g., when commodities intended for consumption are used as seed for planting, is an important issue in agricultural trade that has implications for the establishment of pests and pathogens in an importing country and for the appropriate strength of plant health measures. Consequently, understanding and accurately characterizing the risk of diversion from intended use is highly relevant to policymakers, trading partners, and in trade dispute arbitration. To our knowledge, no risk assessments have ever accounted for the likelihood of diversion from intended use. Here we present an approach to analyzing this risk using diversion of U.S. table stock potatoes to seed for planting by Mexican potato producers as a case study. We use probabilistic pathway models to characterize the movement of white, yellow, and russet potatoes from the United States into Mexico at current and double export volumes. We then model the likelihood of these potatoes being diverted for seed and the subsequent establishment of bacteria, nematode, and virus pests in Mexico. Our approach demonstrates how diversion from intended use can be quantified in one scenario and, in particular, how it can be analyzed to estimate the magnitude of diversion required to produce a high risk of pest establishment.     

Trends in Global Gender Inequality (Forthcoming, Social Forces)

This study investigates trends in gender inequality for the world as a whole. Using data encompassing a large majority of the world's population, we examine world trends over recent decades for key indicators of gender inequality in education, mortality, political representation, and economic activity. We find that gender inequality is declining in virtually all major domains, that the decline is occurring across diverse religious and cultural traditions, and that population growth is slowing the decline because populations are growing faster in countries where there is the greatest gender inequality.     

Towards a Sociology of Disclosure: The Case of Surgical Performance

Despite the increasingly widespread emphasis on the need for transparency in health‐care and elsewhere, there is limited evidence regarding the consequences of disclosing medical performance data. The evidence is disparate and has not been synthesised in a coherent way. This paper focuses on surgical performance, whose measurement is generally often seen as straight forward. It begins by outlining the context for understanding the publication of such data and then presents an analytical framework as a vehicle for conceptualising the nature of disclosure in surgery and health‐care more generally. The framework addresses key dimensions concerning one surgical specialty (cardiac surgery) and its relationship with a range of stakeholders in an English context. In particular, we examine the interaction between surgeons and between surgeons, patients, managers and policy‐makers. These relationships are framed in terms of choice and calculativeness, strategies and tactics, and trust, and need to be understood at micro, meso and macro levels. We conclude by considering how this framework provides a research agenda for a sociology of disclosure.     

Building a youth-led movement to keep young people out of the adult criminal justice system

Through the lens of the Youth Art & Self-empowerment Project (YASP), this article explores the impact that the adult criminal justice system has on young people and how young men and women in Philadelphia are organizing to challenge that system. YASP has developed an innovative model for supporting and training young people in Philadelphia's adult jails and recently released from the adult jails to build a youth-led movement to repeal adult transfer laws in Pennsylvania. Through stories of personal experience and collective struggle, this chapter illustrates the power of young people taking back control of their city, their state, and their own destinies.